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6.
Challenges
2015
How to ensure services
interact
consistently, avoid
dependency hell
How to migrate & scale
quickly, ensure
compatibility
How to avoid n X n
different configs
Running on any
available set of
physical resources
(public/private/
virtualized)
Assembled by
developers using
best available
services
Thin app on
mobile, tablet

13.
MultiplicityofGoods
Multiplicityof
methodsfor
transporting/storing
DoIworryabout
howgoodsinteract
(e.g.coffeebeans
nexttospices)
CanItransport
quicklyandsmoothly
(e.g.fromboatto
traintotruck)
Solution: Intermodal Shipping Container
…in between, can be loaded and
unloaded, stacked, transported
efficiently over long distances,
and transferred from one mode
of transport to another
A standard container that is
loaded with virtually any
goods, and stays sealed until
it reaches final delivery.

15.
and spawned an Intermodal Shipping Container Ecosystem
• 90% of all cargo now shipped in a standard container
• Order of magnitude reduction in cost and time to load and unload ships
• Massive reduction in losses due to theft or damage
• Huge reduction in freight cost as percent of final goods (from >25% to <3%)
 massive globalizations
• 5000 ships deliver 200M containers per year

16.
Static website Web frontendUser DB Queue Analytics DB
Development
VM
QA server Public Cloud Contributor’s
laptop
Docker is a shipping container system for
code
MultiplicityofStacks
Multiplicityof
hardware
environments
Production
Cluster
Customer Data
Center
Doservicesandapps
interact
appropriately?
CanImigrate
smoothlyandquickly
…that can be manipulated using
standard operations and run
consistently on virtually any
hardware platform
An engine that enables any
payload to be encapsulated
as a
lightweight, portable, self-
sufficient container…

20.
Why containers matter
Physical Containers Docker
Content Agnostic The same container can hold almost any
type of cargo
Can encapsulate any payload and its
dependencies
Hardware Agnostic Standard shape and interface allow same
container to move from ship to train to
semi-truck to warehouse to crane
without being modified or opened
Using operating system primitives (e.g. LXC)
can run consistently on virtually any
hardware—VMs, bare metal, openstack,
public IAAS, etc.—without modification
Content Isolation and
Interaction
No worry about anvils crushing bananas.
Containers can be stacked and shipped
together
Resource, network, and content isolation.
Avoids dependency hell
Automation Standard interfaces make it easy to
automate loading, unloading, moving,
etc.
Standard operations to run, start, stop,
commit, search, etc. Perfect for devops: CI,
CD, autoscaling, hybrid clouds
Highly efficient No opening or modification, quick to
move between waypoints
Lightweight, virtually no perf or start-up
penalty, quick to move and manipulate
Separation of duties Shipper worries about inside of box,
carrier worries about outside of box
Developer worries about code. Ops worries
about infrastructure.

21.
Why Developers Care
• Build once…run anywhere
• A clean, safe, hygienic and portable runtime environment for your app.
• No worries about missing dependencies, packages and other pain points during
subsequent deployments.
• Run each app in its own isolated container, so you can run various versions of libraries
and other dependencies for each app without worrying
• Automate testing, integration, packaging…anything you can script
• Reduce/eliminate concerns about compatibility on different platforms, either your own or
your customers.
• Cheap, zero-penalty containers to deploy services? A VM without the overhead of a VM?
Instant replay and reset of image snapshots? That’s the power of Docker

22.
Why Developers Care
―Docker interests me because it allows simple environment
isolation and repeatability. I can create a run-time environment
once, package it up, then run it again on any other machine.
Furthermore, everything that runs in that environment is isolated
from the underlying host (much like a virtual machine). And best
of all, everything is fast and simple.‖
-Gregory Szorc, Mozilla Foundation
http://gregoryszorc.com/blog/2013/05/19/using-docker-to-build-firefox/

26.
Why are Docker containers lightweight?
Bins/
Libs
App
A
Original App
(No OS to take
up space, resources,
or require restart)
AppΔ
Bins/
App
A
Bins/
Libs
App
A’
Guest
OS
Bins/
Libs
Modified App
Union file system allows
us to only save the diffs
Between container A
and container
A’
VMs
Every app, every copy of an
app, and every slight modification
of the app requires a new virtual server
App
A
Guest
OS
Bins/
Libs
Copy of
App
No OS. Can
Share bins/libs
App
A
Guest
OS
Guest
OS
VMs Containers

31.
Alternative 1: Impose Consistent Dev Environment
Description:
• Try to impose a consistent
development environment
Challenges:
• Goes against 20 years of
development trends
• Can’t predict what will be
needed for next app
• Doesn’t work outside confines
of the enterprise (e.g. at
customer sites)
Reduce#rowsviapolicy

33.
Alternative 3: Hardware Virtualization
Description:
• Create a virtual server for each
app
Challenges:
• HW Virtualization great for
many uses cases (e.g. server
consolidation)
• But..
heavyweight/expensive/slow
• Need different VM for different
hypervisor environments
• Has to be completely redone
for each new application or
version
• Not good for scale out, hybrid
clouds, massive
clustering, iterative
development

34.
Alternative 4: Package Automation
Description:
• Automate creation of different
VMs for different
Challenges:
• A great solution for certain
distribution challenges, but…
• VMs are still
heavyweight/expensive
• Has to be completely redone
for each new application or
version
• Better idea: combine
containers plus automation